Direct push propulsion unit



April 28,1953 J. D. MENDEZ LLAMOZAS 2,636,340

DIRECT PUSH PROPULSION UNIT Filed Oct. 9, 1948 2 SPEETS-SHEET 1 I 13 1a w INVENTOR ATTORNEY Ap 1953 D. 'MENDEZ LLAMOZAS 2,636,340

' .DIRECT PUSH PROPULSION UNIT Filed Oct. 9, 1948 2'SHEETSSHEET 2 INVENTOR ATTORNEY Patented Apr. 28, 1953 Juan D. Mendez Llamozas, Caracas, Venezuela Application October 9, 1948, Serial No. 53,740

Claims. (01. 60-7 The present invention relates to a direct push motor or propulsion unit and, in particular, to

a propulsion unit for automotive or self-pro-' pelled vehicles. The term vehicle is herein used in a broad sense to include aircraft, land craft and water craft, including both surface and sub-surface craft.

The propulsion system in accordance with the present invention is basically different from conventional means for propelling vehicles. Ordinarily, a vehicle is propelled by a force acting against an external medium. This medium is the road surface in the case of automobiles, steel rails in the case of locomotives, water'in the case of watercraft and air in the in case of aircraft. Propulsion is secured by reaction of the propelling force against such media.

In accordance with the present invention, the reaction for propelling the vehicle is created not in an adjacent or surrounding medium but inside of the propulsion unit itself. For that reason, the apparatus is referred to as a direct push motor or propulsion unit, the propelling force being exerted without utilizationof conventional means such as wheels, screws, paddles, propellers, etc., acting on an outside medium.

The principle of operation of the direct push propulsion unit in accordance with the present invention is similar to the phenomenon observed in the recoil of a large caliber gun. In the firing of a gun, a high gas pressure is momentarily created in the barrel of the gun behind the projectile. This gas pressure exerts a force on the projectile and an equal and opposite force on the barrel .of the gun. Upon the sudden release or discharge of the projectile, the recoil of the gun creates a thrust tending to move the gun carriage in a direction opposite to the di-' In the' rection of movement of the projectile. case of a gun, the thrust created by the recoil is an undesirable by-product of the firing of a projectile and is ordinarily dissipated by suitable recoil mechanism. The magnitude of the thrust created by recoil of a gun, even of mod erate size, as, for example, a 4-inch gun, is indicated by the size and power of the recoil inech-e anisnr provided and by the extent of move-' manner is utilized'to propel a vehicle or -perform other useful work.

In .the presently preferred form ofthe direct push propulsion motor in accordance with the present invention, a-chamber or cylinder corresponds to the barrel of a gun while a piston corresponds to the projectile. The. gas pressure corresponding to that create'dfby the explosion of the propulsive charge is provided by the com:

pression of air or other gasin the cylinder. [The piston is moved in onedirection by power-driven means to compress the gas in the cylinder.

When maximum compression is reached, the

. thrust is transmitted to the vehicle on which cordance with the present invention suppliesv many hundreds or thousands of impulses per minute so that a continual propelling force is exerted on the vehicle.

The invention will be more fully understood from the following description of the embodiments shown by way of example in the accompanying drawings in which Figs. 1 to 4 are diagrammatic views in longitudinal vertical section of a direct push motor or propulsion unit in accordance with my invention, showing the motor in successive stages of its cycle of operation.

Fig. 5 is a fragmentary longitudinal sectional view corresponding to the left-hand portion of Fig. 1 but on an enlarged scale and showing addition-al controls for the motor.

Figs. 6 and 7 are views similar to Figs. 1 to 4 but show another embodiment with a reversing control.

The direct push motor or propulsion unit shown diagrammatically in Figs. 1 to 4 comprises a motor block or casing in having one or more cylinders II and a crank case portion 12. Apiston [3, preferably provided with one ormore piston rings, is reciprocable in the cylinder l l and is connected by a wrist pin M with one' end of a connecting rod IS. The other end of the connecting rod I5 is provided with a crank pin l6 carrying a roller l1 adapted to engage a driving member l8.

The driving member I8 is carried by a power I shaft 20 which is rotatably supported by suitable bearings in the crank case portion of the motor block and is driven by a suitable power source such, for example, as an internal combustion engine electric motor or turbine. The driving member I8 is hence power-driven. The connecting rod l5, and hence the cylinder l3, are operatively connected with the driving member I8 by providing the driving member with an opening or recess 2! into which-the crank pin I6 ofthecoifinectin'g rod [5 projects. As shown in the drawings, the opening 2| is es sentially the shape of a segment of a circle having an arcuate side 22 and a straight side 22' which is parallel to, but offset from, a diameter of the driving member l8. One end of the opening 2| is rounded with approximately the same radius as that of the roller IT on the crank pin l6, as indicated at 23, while at theother end there is provided a curved socket portion 24 which likewise is of approximately the same radius is" theroller i1. As will-appean-more fully from the following de'sciiptionof'the cycle f operation of the pro ulsion unit, the engagemerit of the crank p'in IS'with the opening- 2| of the driving member l8 provides a driving connectionbetween'the driving member and the piston in certain portions of the c'ycle while at thesame time providing "for the quick release and free movement of the'pi'ston in other-portions-of the cycle. The shape of the recess "2| is suehjas to ring about th'release of the" piston when'it islas near'aspossible to its basi tionborrespondin'g to the'highest compression of the fluidinsidethe chamber or'cylinderin which it operates. Inthis positionof the pie-- ton the straight side 22* of the recess 2! should be substanti-all in line with the connecting rod, so that when the piston issuddenly'r leased its full"movement is wholly uninhibited by the driving member. Itwillbeunderstood that-any shape of the recess permitting "an independent movement a iven moment between the piston and the driving irllilbefis-to be conside ed as included in'the' claims.

The direct push motor or propulsion unitis mounted in' or on the vehicle which it is -i'm tended to propel with the axis-"of the"cylinder "approximately parallel "tothe direetioh of movement oi the vehiclef-"While only-one'cylim der has been shown; it will be understood that the motor may be provided "withany desired numberof "cylinders to provide the total thrust required.

The cycle ofoperation "of the I direct push motor or propulsion unit in aocordahce wi-th the invention is illustrated in Figs; 1 to 4" of the drawings. The driving member 18 is rotated in a "counter 'clockwise 1 direction; being driven at th'desired speed by a suitable prime mover as indicated above. Fig. 1 shows the beginningofthe cyelejoi operati'onwith-the piston is at substahtially the bottomof its stroke and with' the crank pin it resting in the socket portion 24 of the openings! in the driving member. As

the driving member rotates, it'acts throughthe crank pin is, coniie'e'ting'rou l5 and Wrist pin lite niove'the piston lt'to the leit'towai-dsthc top of the cylinder, thereby compressingthe air in the cylinder. The compression of'air in the cylinder results in 'a'io'rce F acting 'on' the top of the pistonand an equal and opposite rorce Es acting on the he'ad-ofthe' cylinder. Fig. 2

shows an intermediate stage hrwhich the driving'member has rotated approximatelyeildegrees from theposition shown in-Fig. 1 and.

the air in the cylinder is being compressed. The rotation of the driving member and the resulting movement of the piston towards the left continue until the piston has reached the position shown in Fig. 3. At this point, the piston has reached the top of its stroke. The air in the cylinder is, at this point, subjected to maximum compression and, hence, the force H actingonthe piston andtheequal and opposite force Fe' acting on'the head or the. cylinder have been increased to their maximum values. As the forces F and Fe are equal and opposite, they are in complete equilibrium.

As the'poiht of full compression is reached, the crank pin i5. passes over the head center position and is suddenly released, thereby severing-the driving connection between the driving member is and the piston l3. The piston is thereby abruptly freed. The force F up to now, has been transmitted through the connecting rod IS to' thedriving member iii and hence through the shaft 2-;- to the casing of themoto'r. thereb balancing "the force Fe" acting on'the pistonhead. Upon the connection between the piston and the driving member being suddenly broken as, described above, so that the piston is no longer restrained, the force-F i-is,ineffect, nullified. The equilibrium between Fe and F is thereby destroyed, leaving-only the force Ft acting on the cylinder head. This reaction protion relative tothe-driving-member will depend on the rate of movement of the piston after it has been freed relative to the rate of movement of'the driving'member. Becauseof-centrifug'al'fforce, the crank pin it Will'ordinarily follow the outer arcuate side iii-of the opening 2! although it is unrestrained laterally as-tvell as in a directioh lengthwise "of the'opening. the piston moving iirthe direction of the arrow shown'in Fig. 4" reaches the end of its stroke, the continued rotation'of the driving member l8 causes'the' crank pin I 6 again to be received in the isocket "portion 2a of the opening 2!, whereupon the cycle of operations: is repeated. It will be seen that at thepoint atwhich driving connection is reestablished between the piston and the driving member I B, the driving member is approximately in; or slightly in "advance of, the position "shown in "Fig. 1 and-thedirection of movement oi 'the' socket 24 is upwards as viewed in this figure and thus substantially at right angles to the direction of reciprocationof the piston. Hence, there can be-no substantial amount of shock in "the 'reengagemnt ofthe crank "pin with the socket; even-though there may be some difference ii -velocity immediately prior to'reengage'ment. Thus; even if thecr-ank pin were momentarily standing still, the -only shock would f be: the small amount attributable to the"weight'of*the crank. pin and-theadia cent portion of thecohnecting rod. After the driving'cohnection has'been reestablished, the acceleration of the piston is gradual; the curve of acceleration being substantially sinusoidal. It is hence normally "unnecessary to make any Special ploViSiOfis for Gll'Shi'Oliil'lQ the contact, be-

tween the crank pin and the socketi24..'1However, if desired, the s'ocket24 may be provided with a suitable buffer portion, or the crankipin 16 may be constructed or mounted to provide buffer action.

Comparing the cycle of operation of the direct push motor in accordance with the present invention with the firing of a gun, it will be seen that the compression of air or, gas .in the cylinder H, as illustrated in Figs. 1, 2 and 3, corresponds to the loading of the gun. The cylinder Il may be taken as representing "the barrel of a gun while the piston I3 is the projectile. The compressed air provides gas pressure corresponding to thatcreated by the explosive charge. The sudden breaking of the driving connection between the piston and the driving member I5 (Figs. 3 and 4) corresponds to the firing of the gun. The projectile, or piston i3, movesireely in one direction while the recoil exerts a force on. the. barrel, or cylinder H, in the opposite direction. It is this recoilwhich, in accordance with the present invention, is used for propelling the vehicle. There is hence one push on the vehicle for every complete turn of the power shaft 20, one-half of the revolution being utilized for loading and the other half-revolution for explosion with its resulting recoil. When the motor is provided with a plurality orcylinders, it will be understood that the phaserelalation of the pistons in the respective cylinders can be so arranged as to provide a substantially continuous thrust. I v It has been found preferable to drive the driving member l8 at such speed that the socket 24 picks up the crank pin 16 substantially simultaneously with the end of the outward movement of the piston. .However, the speed may be regulated as desired. While thedriving member I8 has been shown in the form of a wheel, it will be understood that the invention is not limited to this specific form, as the driving member may be of other shapes. Moreover, the intermittent driving connection between the driving member and the. piston so as to compress the gas in the cylinder and then suddenly released the piston, may be provided by other means such, for example, as a cam and cam follower, or a Scotch yoke and pin, instead of by the particular form of driving member and connecting rod illustrated by way of example in the drawings.

The'amount of thrust exerted by the direct push propulsion unit in accordance with the invention may be varied by varying the degree of compression of gas in the cylinder and thereby r varying the magnitude of the forces F and Fe. This can be done in severalways. For example; means may be provided for varying the compression ratio, as by varying the distance be tween the head of the piston and the power shaft 20 or by otherwise varying the volume of the cylinder when the piston is at the top of its stroke as, for example, by means of a chamber of variable volume communicating with the top portion of the cylinder or by means of a displacement member which is movable ayariable amount into the cylinder to decrease its volume. Alternatively, the top pressure of gas in the cylinder can be controlled by means of a valve arrangement permitting a portion of the gas to escape during the compression stroke. One such arrangement is illustrated diagrammatically by way of example in Fig. 5.

In the embodiment illustrated in Fig. 5, the top or closed end of the cylinder H is provided with an outlet port or orifice. 30 shaped to provide a conical seat 3| for a valve member 32: The valve member'ismovable towards and away from the valve seat 3|. and isguided in its movement by a short valve stem 33 slidablyheld by aspider 34. A spring 35 acts to hold the valve member 32 on its seat; the forceof the spring being variable by means of a screw member 36.

The valve member 32' acts as a release valve to control the'maximum pressure created in the cylinder. If the pressure becomes great enough to unseat the valve member 32 against the pressure of the spring 35, a portion of the air in the cylinder-is permitted to escape. The maximum pressure attained in the'cylinder and, hence, the thrust produced bythe propulsion unit can be increased by increasing'the pressure of the spring on the valve member 32 and, conversely, can be decreasedby decreasing the pressure of the spring.

: In order to provide for the subsequent": replacement ofair permitted to escape through the valve 32, the cylinder" II is also provided with an inlet port or conduit providing a shoulder or seat 4| for a valve disc 42 which is normally held on its seat by a relatively light spring .43. If additional air is needed in the cylinder, it can be drawn in through the port 40. The valve 42 blocks the exit of air thus drawn in.

The inlet valve 42 will ordinarily admit air to the cylinder whenever the pressure inside the cylinder falls below atmospheric pressure. In some instances, however, it may be desirable to limit the amount of air in the cylinder so that the pressure falls below atmospheric for a portion of each stroke. For this purpose, theinlet port 40 is controlled by. a second valve 45 which is shown in the form of a plug valve having an apertured conical plug 46 rotatable by a handle 41. When the plug valve 45 is opened by turning the valve plug 50 as to bring its aperture into alignment with the opposite ports of the valve body, air is admitted to the cylinder ll under control of the check valve 42-, as described above. When the plug valve 45 is closed, the admission of additional air to the cylinder II is prevented.

Figs. 6 and '7 illustrate additional controls which permit reversing the direction of the thrust produced by the motor as well as controlling the amount of the thrust. The embodiment shown diagrammatically in Figs. 6 and 7 comprisesa cylinder 51 adapted to be mounted on the vehicle and closed at both ends by cylinder heads 52 and 53. A piston 54 is reciprocable in the cylinder by means of apiston rod 55 ,extending out through a stuffing gland 56 with which one of the cylinder heads 53 is provided. The piston rod 55 is pivotally connected at its outer end to one end of a connecting rod 51, the other end of which is provided with a crank pin 58 adapted to work in an opening 59 in a power-driven driving member BI carried by a power shaft 62. The arrangement of the connecting rod and driving member is essentially thesame as in the embodiment of Figs. 1 to 4.

The cylinder 5| is provided adjacent its opposite ends with one or more outlet ports 64 and 65. A slide valve member 56 is adapted to be moved longitudinally of the cylinder so as to cover either of the ports 64 or 65 or to be in an intermediate position between them so that both ports are left open. With the port 64 closed and the port 65 open, as illustrated in Fig. 6, the motor works exactly the same as that of Figs.

7 1 to 4. With the sleeve valve 56 in position to close the" port 65 while-leaving the port-64 open. asillustr ated'in Fig. 'l, "the action is the same exceptthat the direction of :thrust is reversed since the piston compresses air in the right hand end of the cylinderas the piston is moved towards the right by the drivimg:-member- 6| acting through 'theiconnecting rod i'l'and the piston rod-55. With the slide valve member E6 inanintermediate positionyso-that' both ports 61 and B5 are open; no thrust isproduced, the motor thus being in neutra By having the port 54 or65'partial1y closed instead of fully closed, a reduced thrust is obtained in the manner described in connection with the embodiment-ofFig 5. The amount of thrust, as well as'th'e direction'of thrust, can hence be varied asdesired. r

Inplace of the slide valve illustrated diagrammatically in Figs. 6 and *7, the openings atthe opposite ends of the cylinder 5! may becontrolled by other valves of suitable type; For example, a valve arrangement similar to that shown in Fig. 5 may be provided at each endof the cylinder 5!. "While the invention and its operation: have been described withreference to the embodiments shown by way of example "in the drawings, it will be understoodthatthe inventionis in no way limitedto these particular embodiments. For exampla'other elastic media, suchas springs, may be used in place of thecompressible gas, Still other modifications within the scope of the appended claims will be apparent to those: skilled in the art.

What I claim and Patenti-s: I

15A direct push propulsion unit comprising a cylinder, a piston'reciprocable in the cylinder, a power driven rotary member having an' offcenter slot extending in-anapproximately chordwise direction partway across said member, and a connecting rod connected at one end with the piston and having-at the otherend a crank pin portion freely movable in the slot in the rotary member and adapted to engage one end of the slot to provide apositive power connection between the power driven rotary member and the piston'to drive the piston in one direction to compress an elastic medium in the cylinder and thereby establish aiorce acting onthe cylinder and'an-equal and opposite force acting on the piston, and, by the freemovement of the crank pin in the slot, to release the piston for free "movement in the opposite direction upon completion of the compression stroke thereby nulliiying the forceacting on the piston and leaving unbalanced the force acting on the cylinder to create aunidirectional thrust on the cylinder. r

2. A direct push propulsionunit according to claim 1, in which the power driven rotary member is a wheel having therein-aslot corresponding in shape to the segment of a circle.

3. A direct push propulsion unit according to claim 1, in which the elastic medium in the cylinder is a'compressible gas and in which means is provided for increasing and decreasing the degree of-compression. 1

desire to secure by Letters s.

4. A direct push propulsion unitcomprising a block, a piston reciprocable relative to saidjblock. an elastic medium compressible by movement of the piston relative to the block in one direction. said elastic medium, whencompressed, tending to move the piston relative to theblock in the opposite direction, a power-driven .rotarymember havingxan abutment surface disposed eta distance from the axis *ofarotation of said rotary member, a connectingrod connected at one end withthe pistonand having at the other ,end 'a bearing portion adapted to bear on said abutment.

surface of the rotary member to provide a positive power connection between the power-driven rotary member and the pistonto drivethe-piston in a direction to compress saidelasticqmedium and to he disengaged from said abutment surface upon completion ofsaid compressive movement to permit free movement of th pistonrelative' to the block in the opposite direction unrestrained bysaid rotary member and means for guiding the bearing portion of the connecting rod back into engagement with said abutment surface inpreparation for a succeeding cycle of operation in like manner.

5. A direct push propulsion unit comprising a block, a piston reciprocable relativeto said block. an elastic medium compressible by movement of the piston relative to the block in one direction. said elastic medium; when compressed, tending to move the piston relative to the block in the opposite direction, a power-driven rotary .mem her having a seat disposed at a distance from the axis of rotation of said rotary member, a-connecting rod connected at one end to said piston-and having at the opposite end abearingportion adapted to be received in said seat to provide a positive power connection between the powers driven rotary member and the piston to drivethe piston in a direction to compresssaid elastic medium during approximately half a revolution of said rotary member, said bearing portion of the connecting rod being thereupon disenga ed from said seat by the reaction of said elastic medium to permitiree movement of the piston relative to theblocl-z in the opposite direction unrestrained by said rotary -member during the remaining italic-evolution and means for guiding the bearing portion of the'connectins rod back into said seat in preparation fora succeeding cycle of operation in like manner.

, JUAIID. MENDEZ LLAMOZAS.

References Cited in the me ofthispatent UNITED STATES-PATENTS France Oct. 11, 1921 

